i am trying to install oracle 9.0.1 on iBM-AIX 4.3.but when i run runInstaller script i got the follwonig below error

error in writting to directory /tmp/Oinstall. please ensure that this directory is writable and has alleast 25MB of disk space.Installation can't continue

then i check the size of /tmp directory like #df -k /tmp
it showing 2GB, and i have given the permision to /tmp directory #chmod 777 /tmp
then i run the runInstaller again i got the same error.please any one has idea bout that.quick respose will be higly appreciated.thanks a lot in advance.